1. Field of the invention
The present invention relates to methods of manufacturing an active material and an electrode which are used in chargeable electrochemical devices such as lithium-ion secondary batteries and electric double-layer capacitors, and the active material and electrode manufactured by these manufacturing methods.
2. Related Background Art
In order to improve the cycle characteristic and safety of positive electrode active materials in lithium-ion secondary batteries, it has recently been tried to add F (elemental fluorine) to the surfaces of the positive electrode active materials.
For example, patent literature 1 discloses a particulate lithium-ion secondary battery positive electrode material represented by a general formula of LiaCobAcBdOeFf (where A is Al or Mg, B is a group IV transition element, 0.90≦a≦1.10, 0.97≦b≦1.00, 0.0001≦c ≦0.03, 0.0001≦d≦0.03, 1.98≦e≦2.02, 0≦f≦0.02, and 0.0001≦c +d≦0.03), in which elemental A, elemental B, and fluorine evenly exist in the vicinity of particle surfaces.
Patent literature 2 discloses a lithium-nickel-cobalt-manganese-fluorine-containing composite oxide having an R-3m rhombohedral structure represented by a general formula LipNixMn1−x−yCoyO2-qFq (where 0.98≦p≦1.07, 0.3≦x≦0.5, 0.1≦y≦0.38, and 0<q≦0.05), in which the half-width of the diffraction peak of a (110) plane whose 2Θ is 65±0.5° in the X-ray diffraction using a Cu—Kα line is 0.12 to 0.25°. Its paragraph [0050] states: “In the lithium-nickel-cobalt-manganese-fluorine-containing composite oxide of the present invention, a mixture to which a fluorine compound is added in addition to the lithium compound is used for firing. Examples of the fluorine compound include lithium fluoride, ammonium fluoride, magnesium fluoride, nickel fluoride, and cobalt fluoride. A fluorinating agent, such as fluorine chloride, fluorine gas, hydrogen fluoride gas, or nitrogen trifluoride can also be allowed to react” Its paragraph [0020] states: “In the present invention, it is preferable that fluorine atoms are eccentrically located on the outer-layer portion of the lithium-nickel-cobalt-manganese-fluorine-containing composite oxide. The presence of the fluorine atoms located evenly in the particles of the composite oxide is not preferable because the effect of the present invention is difficult to develop.”
Citation List
Patent Literature 1: WO20041030126 pamphlet
Patent Literature 2: WO02005/028371 pamphlet